This gene is a member of the G-protein coupled receptor 1 family and encodes a multi-pass membrane protein that localizes to the endoplasmic reticulum. The protein binds estrogen resulting in intracellular calcium mobilization and synthesis of phosphatidylinositol 345-trisphosphate in the nucleus. This protein therefore plays a role in the rapid nongenomic signaling events widely observed following stimulation of cells and tissues with estrogen. Alternate transcriptional splice variants which encode the same protein have been characterized. [provided by RefSeq Jul 2008]